1. Field of the Invention
The present invention relates to portable wireless communications devices, such as portable telephones and pagers, which comprise a circuit board for wireless communication and a cell for supplying power to the circuit board, both housed in a flat casing.
2. Background of the Invention
FIG. 7 shows the construction of a conventional portable telephone in section orthogonal to the longitudinal direction thereof. A circuit board (7) is installed inside a flat casing (9) comprising a front case (91) and a rear case (92) which are made of a synthetic resin. A peripheral wall (95) and a bottom wall (96) which are molded integrally with the rear case (92) form a cell chamber for housing a cell (2) therein. A lid (93) for closing the cell chamber is removably attached to the rear case (92).
With portable telephones which need to be compacted and reduced in thickness, the electronic parts to be mounted on the circuit board and the cell have been made compact almost to the greatest possible extent, and extreme difficulties are encountered in making portable telephones more compact and thinner by compacting the components.
For example, even if it is attempted to reduce the thickness of the telephone shown in FIG. 7, the circuit board (7) having a large number of electronic parts mounted thereon and the cell (2) have been reduced in thickness to the limit as stated above, while the lid (93) and the casing (9) are also limited to about 0.7 mm in thickness in view of the problems as to the strength. The bottom wall (96) of the cell chamber is indispensable for supporting the cell (2) in the chamber and blocking water ingressing into the cell chamber to protect the circuit board (7) from the water.
The front case (91) and the rear case (92) providing the casing (9) are molded from resin with use of a pair of molds, respectively. These cases need to be designed in shape with consideration given to the draft of each mold. With the rear case (92), for example, a parting line Axe2x80x94A for the pair of molds is located at the position of the boundary between the cell chamber peripheral wall (95) and the cell chamber bottom wall (96), and the peripheral wall (95) needs to be shaped in section so as to incline at a specified angle xcex8 (e.g., 3 deg) as shown in FIG. 12(b).
Assuming that the peripheral wall (95) has a height H, for example, of 10 mm, the inclination of the wall (95) therefore gives an excess of 0.52 mm to the lateral width thereof, with the result that the distance B1xe2x80x2 from the side face of the cell (2) to the outer peripheral surface of the rear case (92) increases by the excess of 0.52 mm, thus entailing the problem of increasing the overall width of the casing (9).
An object of the present invention is to provide a novel construction for portable telephones or like portable wireless communications devices which serves to make the device more compacted and thinner than conventionally.
The present invention provides a first portable wireless communications device which comprises a casing (1) formed with a peripheral wall (5) defining a cell chamber and having an opening at each of an inlet side of the cell chamber and a bottom side thereof, the opening at the inlet side of the cell chamber being provided with a lid (13) removably attached to the casing (1) for closing the opening, the opening at the bottom side of the cell chamber being fixedly provided with a sheet for closing the opening.
The sheet is in the form of a flat plate or tray. The flat platelike sheet (33) has a contour extending outwardly of the opening of the peripheral wall (5) at the cell chamber bottom side. The traylike sheet (3) has a bottom wall (31) closing the opening of the peripheral wall (5) at the cell chamber bottom side, and a side wall (32) extending from an outer periphery of the bottom wall (31) and in intimate contact with the peripheral wall (5).
The sheet included in the telephone of the invention described is made of PET, synthetic resin or metal, and can be thinner than the conventional cell chamber bottom wall of synthetic resin which is molded integrally with the casing. Accordingly, the communications device of the invention can be reduced in thickness by an amount corresponding to the difference in thickness between the sheet and the conventional cell chamber bottom wall.
Stated specifically, the sheet has a rear surface in contact with a surface of a circuit board (7). An external force acting on the cell in the cell chamber is then received by the surface of the circuit board (7) through the sheet.
The casing (1) is molded from a resin with use of a pair of molds, and the peripheral wall (5) is molded from the resin with a parting line of the pair of molds positioned at an intermediate portion of thickness of the casing. The casing thus constructed can be smaller in lateral width than in a portable communications device which comprises a cell chamber peripheral wall (5) having the same height as that of the invention, and a casing molded from a resin, with the same draft [angle xcex8 in FIG. 12(a)] as in the invention given and with a parting line of a pair of molds positioned at one of the ends of the casing in the direction of its thickness.
More specifically, the peripheral wall (5) comprises a first peripheral wall portion (51) at the cell chamber inlet side and a second peripheral wall portion (52) at the cell chamber bottom side, with the parting line serving as a boundary between the wall portions (51), (52), the peripheral wall portions (51), (52) defining respective spaces enlarged in a direction away from the parting line, the first peripheral wall portion (51) projecting at the position of the parting line toward a center of the cell chamber beyond the second peripheral wall portion (52) to form a stepped portion (53) between the peripheral wall portions (51), (52). With this specific construction, the cell can be loaded into the cell chamber with ease since the first peripheral wall portion (51) at the cell chamber inlet side provides a guide face for loading.
With the stepped portion (53) formed positively between the first and second peripheral wall portions (51), (52), the first peripheral wall portion (51) can be caused to project beyond the second peripheral wall portion (52) at all times at the position of the parting line despite molding errors, whereby the cell can be guided smoothly.
Further stated specifically, an outer end of the side wall (32) of the traylike sheet (3) is in engagement with the stepped portion (53) of the peripheral wall (5). This effectively obviates the likelihood that the water drops ingressing into the cell chamber will pass between the side wall (32) of the traylike sheet (3) and the chamber wall (5) to wet the circuit board (7).
The side wall (32) of the traylike sheet (3) is affixed to a surface of the second peripheral wall portion (52) of the peripheral wall (5). An external force acting on the cell in the cell chamber is then received by the traylike sheet (3). Moreover, the water drops ingressing into the cell chamber can then be more effectively prevented from passing between the side wall (32) of the traylike sheet (3) and the chamber wall (5) to wet the circuit board (7).
The present invention provides a second portable communications device which comprises a casing (1) molded from a resin with use of a pair of molds and formed with a peripheral wall (5) defining the cell chamber, the peripheral wall (5) being molded from the resin with a parting line of the pair of molds positioned at an intermediate portion of thickness of the casing, the peripheral wall (5) having an opening at each of an inlet side of the cell chamber and a bottom side thereof, the opening at the inlet side of the cell chamber being removably provided with a lid (13) for closing the opening.
The casing thus constructed can be smaller in lateral width than in a portable communications device which comprises a cell chamber peripheral wall (5) having the same height as that of the invention, and a casing molded from a resin, with the same draft [angle xcex8 in FIG. 12(a)] as in the invention given and with a parting line of a pair of molds positioned at one of the ends of the casing in the direction of its thickness.
Stated specifically, the opening of the peripheral wall (5) at the bottom side of the cell chamber is fixedly provided with a sheet for closing the opening.
The sheet is in the form of a flat plate or tray. The flat platelike sheet (33) has a contour extending outwardly of the opening of the peripheral wall (5) at the cell chamber bottom side, the outward extension being in intimate contact with an end face of the peripheral wall (5). The traylike sheet (3) has a bottom wall (31) closing the opening of the peripheral wall (5) at the cell chamber bottom side, and a side wall (32) extending from an outer periphery of the bottom wall (31) and in intimate contact with the peripheral wall (5).
The sheet included in the specific construction described is made of PET, synthetic resin or metal, and can be thinner than the conventional cell chamber bottom wall of synthetic resin which is molded integrally with the casing. Accordingly, the communications device of the invention can be reduced in thickness by an amount corresponding to the difference in thickness between the sheet and the conventional cell chamber bottom wall.
More specifically, the peripheral wall (5) comprises a first peripheral wall portion (51) at the cell chamber inlet side and a second peripheral wall portion (52) at the cell chamber bottom side, with the parting line serving as a boundary between the wall portions (51), (52), the peripheral wall portions (51), (52) defining respective spaces enlarged in a direction away from the parting line, the first peripheral wall portion (51) projecting at the position of the parting line toward a center of the cell chamber beyond the second peripheral wall portion (52) to form a stepped portion (53) between the peripheral wall portions (51), (52). With this specific construction, the cell can be loaded into the cell chamber with ease since the first peripheral wall portion (51) at the cell chamber inlet side provides a guide face for loading.
With the stepped portion (53) formed positively between the first and second peripheral wall portions (51), (52), the first peripheral wall portion (51) can be caused to project beyond the second peripheral wall portion (52) at all times at the position of the parting line despite molding errors, whereby the cell can be guided smoothly.
More specifically, an outer end of the side wall (32) of the traylike sheet (3) is in engagement with the stepped portion (53) of the peripheral wall (5). This effectively obviates the likelihood that the water drops ingressing in to the cell chamber will pass between the side wall (32) of the traylike sheet (3) and the chamber wall (5) to wet the circuit board (7).
As described above, the first portable communications device of the invention can be made thinner than in the prior art, and the second portable communications device of the invention can be made smaller in lateral width than conventionally.